Specifications

Lumens vs watts,
for people who sell lamps.

What each number means, and how to show both without confusing anyone.

6 min read Updated 23 September 2026

Half your customers still shop in watts. The number stopped meaning what they think it means about fifteen years ago, and correcting them on a product page is a good way to lose the sale. The job is not to educate anyone out of the habit. It is to answer the question they are actually asking.

The short version

• Watts measure what the bulb consumes. Electricity in.
• Lumens measure what the bulb produces. Light out.

When every bulb was incandescent the two moved together, so watts worked as a stand-in for brightness and a generation learned it that way. LED broke the link: a 9 W LED and a 60 W incandescent put out roughly the same light. The habit outlived the physics.

The table people are actually looking for

This is the conversion your customer is doing in their head. Put it on the page and they stop doing it wrong:

• About 250 lm — the old 25 W. A small accent lamp.
• About 450 lm — the old 40 W. A bedside lamp.
• About 800 lm — the old 60 W. The default living-room bulb.
• About 1 100 lm — the old 75 W. A reading lamp you can read by.
• About 1 600 lm — the old 100 W. One ceiling light for a room.

These are approximations and every manufacturer rounds them differently. That is fine: nobody is going to measure. They want to know whether this is a bedside lamp or a room light.

The number that matters more than both

Neither figure tells you what the room will look like, because a lamp is not a bulb. Eight hundred lumens inside an opaque ceramic shade that throws everything at the ceiling, and eight hundred lumens in a bare glass globe, are the same number and two completely different evenings.

What the customer is really asking is: does this light a room, or does it light a corner? Answer that in words, at the top, before any number:

Reads as a pool of light around the chair, not a room light. Around 800 lumens, warm.

How to put it on the page

1. Lumens as the headline number, because it is the honest one.
2. The watt equivalent in brackets, because that is the number in their head. 800 lm (like an old 60 W) costs four words and removes the whole question.
3. The real consumption further down, in the spec table, where the people who care about the electricity bill will go looking for it.
4. Colour temperature beside it, always. Brightness without warmth is half an answer: 800 lm at 2700 K and 800 lm at 5000 K are different products.

If the lamp ships without a bulb

Say so near the title, not in the fine print, and then recommend one: fitting, lumens, temperature. Somebody left to choose a bulb alone will choose badly about half the time, and when the room looks wrong they will not blame the bulb.

Where the numbers stop helping: no spec line tells anyone what a perforated shade does to the wall behind it, or how a linen drum goes grainy and warm when the light is inside it. That part a photograph has to carry.